Positive let-off for loom



Jan. 11, 1966 R. B. GRAY POSITIVE LET-OFF FOR LOOM Filed July 6, 1964 INVENTOR E55? 72.33005 Gxmy United States Patent 3,228,428 POSITIVE LET-OFF FOR LOOM Robert B. Gray, Langdaie, Ala., assignor to West Point- Pepperell, Inc., a corporation of Georgia Filed July 6, 1964, Ser. No. 380,418 1 Claim. (Cl. 139-104) This invention relates to a positive let-01f apparatus for feeding warp yarn to a loom.

The principal object of the present invention is to provide a positive warp let-off apparatus in which there is no nip action on the warp yarn thus making it easier to comb ends back, thread up ends and piece up ends.

Another object of the invention is to provide a warp let-off apparatus having warp let-01f rolls which hold the warp firmly and eliminate slippage.

A further object of this invention is to provide a warp let-off apparatus that requires no operator adjustments on the loom from a full to an empty warp beam.

A still further object of the invention is to provide a warp let-off apparatus that provides an improved control of the width, weight and crimp of the warp yarn.

An exemplary embodiment of this invention is illus trated by way of example in the accompanying drawings in which,

FIGURE 1 is a diagrammatic view of a warp let-off apparatus according to the present invention;

FIGURE 2 is a front view partially broken taken substantially along lines 22 of FIGURE 1; and

FIGURE 3 is a fragmentary top View of a portion of the apparatus taken substantially along lines 3-3 of FIG- URE 1.

Referring to the specific parts shown in the drawing, drive shaft is driven by the loom cam shaft (not shown). The cam shaft of the loom is a counter shaft positively gear driven by gears connected to the crank shaft which is positively gear driven by an electric motor. On the end of the rotating shaft 10 is fixed a worm gear 12 which engages worm wheel 14 secured to shaft 16. Spur gear 18 is secured to the other end of shaft 16 and drives spur gear 20 secured to a shaft 22 through intermediate gear 24 secured to shaft 26. Shafts 16, 22 and 26 are journalled on arms 28 connected to a base plate 30. Rotating shaft 22 is connected to shaft 32 by a clutch 34. Rubber covered let-off rolls 36 and 38 are driven in unison by a chain 40 that passes under tensioning idler sprocket 52 and extends between a sprocket 42 carried on the power shaft 32, a sprocket 44 on the shaft 46 mounting roll 36 and a sprocket 48 on the shaft 50 mounting roll 38. The size of sprockets 44 and 48 are the same. Rubber covered roll 36 is smaller in diameter than roll 38, for instance in the embodiment shown roll 36 is A smaller in diameter than roll 38.

A warp beam 54 and warps S6 spooled thereon are positively drawn over let-off roll 36, under idler roll 58 and then over let-oft roll 38. Idler roll 58 is mounted between the let-off rolls 36 and 38 having its center line lying below a line joining the center of the let-off rolls and spaced therefrom so that there is no nip action on the warps 56. Idler roll 58 is smaller in diameter than let-01f rolls 36 and 38. Thereafter the warps 56 are fed over and under a series of idler rolls 60, 62 and 64 and then on to the loom where they are woven into a cloth. Warp beam 54 is carried on a shaft 66 that is journalled in vertically directed arms 68 integrally mounted on base plates 70. 'On warp beam 54 is fixed a gear 72 whichdrives gear 74 keyed to a fiat belt pulley 76. A leather belt 78 is wrapped around pulley 76 and the ends thereof fastened to the loom so as to provide a light drag or braking action on the warp beam 54. This braking action assures that the warps 56 will peel from the warp beam uniformly so that one side does not lead the other.

ice

The cloth take-up mechanism of the loom is also geared to the loom cam shaft so that there is a positive drive between the let-off rolls 36 and 38 and the cloth take-up mechanism.

The operation of the apparatus is as follows:

When drive shaft 10 rotates it drives worm wheel 14 through worm gear 12. Worm wheel 14 is fixed to one end of the shaft 16 and spur gear 18 fixed to the other end. Spur gear 18 drives spur gear 20 through intermediate gear 24. Gears 18 and 20 are change gears which may differ depending upon the picks per inch and the percent crimp desired. By using two change gears instead of one, the relative speeds can be adjusted more closely. Gear 20 drives sprocket 42 through a clutch 34 that can be disconnected to permit backing up the warps 56 when necessary. Warp let-oif rolls 36 and 38 are covered with rubber and driven by chain 40 that extends between sprockets 42, 44 and 48. The rubber covered let-off rolls 36 and 38 draw the warps 56 positively from the warp beam 54. The warps 56 are unrolled from warp beam 54, pass over let-off roll 36, under idler roll 58, and then over let-off roll 38. Idler roll 58 is so arranged to carry the warps 56 thereunder thereby increasing the surface contact of the warps with each of the let-off rolls 36 and 38. From let-off roll 38, the warps 56 are fed under and over a series of idler rolls 60, 62 and 64 and then to the loom. All of the rolls over which the warps 56 pass are separated so that there is no nip action on the warps. The diameter of let-off roll 36 is slightly less than the diameter of let-oif roll 38 whereby the surface speed of roll 38 is faster than the surface speed of roll 36. The purpose of this is to provide tension on the warps 56 between these rolls so as to hold the warps in firm contact with the roll covering and to eliminate slippage.

The leather belt 78 is fastened at each end to the loom and passes over pulley 76. Pulley 76 is connected to gear 74 which in turn engages gear 72 affixed to warp beam 54 to provide a braking action on the warp beam. The purpose of the brake is to compensate for individual tension variations in the warp ends which were put in during prior processing on the warp beam 54. Without the brake, some of the ends would sag to the floor while those under the highest tension would remain taut as the beam 54 is gradually unwound. The brake therefore simply puts enough drag on the warp beam 54 so that the warp ends will always be under some tension during unwinding.

It will then be seen that there has been provided by this invention a method and an apparatus in which the various objects hereinbefore set forth, together with many practiced advantages, are successfully achieved. As various possible embodiments may be made of the novel feature of the above invention, all without departing from the scope thereof, it is to be understood that all matter hereinbefore set forth is to be interpreted as illustrative, and not in a limiting sense.

I claim:

In a loom having Warp let-off mechanism including a warp beam the improvement comprising: let-off feed means including first and second spacedly removed rubber covered rolls, the second of said rubber covered rolls being driven at a slightly greater surface speed than the first of said rolls, an idler roll mounted between said rubber covered rolls and having its center line lying below a line joining the center of said rubber covered rolls, said idler roll being spaced from said rubber covered rolls whereby nip action is essentially eliminated and being arranged to carry the warp thereunder thereby increasing the surface contact of said warp with each of said rubber covered rolls, means for driving said rolls in unison comprising chain means driven by sprocket means cooperating with gear means adaptable to be operatively connected to loom 3 4 cam shaft means, said gear means including first and sec- 2,757,880 -8/ 1956 La Motte 24278.7 0nd operatively connected spur gears, said second spur 3 04 47 19 2 Edmonds 242 7 7 gear operatively connected to said sprocket means through 3 092 343 6/1963 Beefli 2y42 67 2 a clutch mechanism and means for braking said warp beam including gear means fixedly attached to said warp 5 beam cooperating with belt means through pulley means, FOREIGN PATENTS said belt means adaptable to be operatively connected to 13,714 6/1853 France.

said loom thereby braking said Warp beam.

ROBERT .MA KEY,At' P", E References Cited by the Examiner 10 R c 8 mg Hmaly xamme' UNITED STATES PATENTS DONALD W. PARKER, H. s. JAUDON, 467,036 1/1892 Maertens "139-404 Examine- 

